Aromatic polycarbonate resins have excellent mechanical strength, impact resistance, heat resistance and electric properties and, therefore, are used as engineering plastics in many fields. There are known blends of aromatic polycarbonate with various other resins to utilize the properties of aromatic polycarbonate.
It is known to blend aromatic polycarbonate with polyolefin in order to improve oil resistance of aromatic polycarbonate (for instance, Japanese Patent Publication 13663/1965). However, polycarbonate and polyolefin are poorly compatible with each other by nature, so that it is difficult to attain good physical properties. Accordingly, only a limited amount of polyolefin may be added, resulting in a little improvement.
In order to improve the compatibility, it was proposed to use polyolefin modified with an epoxy group in a blend (Japanese Patent Publication 44897/86). This surely improves the compatibility between polycarbonate and polyolefin to some extent, but the improvement attained cannot be evaluated as being sufficient yet. Impact resistance at low temperatures is insufficient in particular. The amount of the epoxy group must be raised to further improve the above, which however leads to an increase in viscosity and a decrease in processability due to the reaction among the epoxy groups. These are undesirable.
Japanese Patent Publication 13384/68 discloses a composition of polycarbonate blended with an acrylic resin. This intends to utilize pearly gloss caused by insufficient compatibility between the two resins and its application is limited.
It is known to blend aromatic polycarbonate with a polystyrene type resin to improve melt flowability of aromatic polycarbonate (for instance, Japanese Patent Publications 6295/68 and 11551/69). Polycarbonate is, however, incompatible with a polystyrene type resin by nature, so that delamination is caused by a shearing stress during molding and impact strength decreases. That is, good physical properties cannot be attained. There is an instance where an organic low-molecular compound such as phosphoric esters and phthalic esters is added to improve the compatibility (Japanese Patent Publication 11551/69). The compatibility is improved to some extent, which is, however, still insufficient. The amount of the polystyrene type resin added is also limited. As its amount increases, delamination is more actualized and impact resistance decreases more significantly.
There is known a method of reacting aromatic polycarbonate with an oxazoline derivative in the presence of catalyst to prepare a cross-linked resin (Japanese Patent Application Laid-Open 248852/88).
Further, aromatic polycarbonate has drawbacks that its molding process temperature is high; its melt flowability is poor; and its impact strength depends greatly upon thickness. Then, it is known to blend an acrylonitrile-butadiene-styrene copolymer, i.e. ABS resin, with aromatic polycarbonate in order to solve the above drawbacks (Japanese Patent Publication 15225/63 and 11142/76).
The composition of aromatic polycarbonate and an ABS resin has being used in large sized molded products such as auto parts in recent years, which however have a problem that extremely poor strength is found in weld parts where a melt resin joins during molding.
It is also known to mix aromatic polyester with aromatic polycarbonate to make use of both the good moldability and chemical resistance of aromatic polyester and the good impact resistance and high glass transition temperature of aromatic polycarbonate (Japanese Patent Applications Laid-Open 54160/73 and 107354/74). However, a molded product prepared from a composition of aromatic polyester and aromatic polycarbonate has a problem that it has poor melt stability so that a Vicat temperature lowers during molding accompanied with residence of the resins.
An attempt was made on a resin composition containing aromatic polycarbonate to improve its mechanical strength, heat resistance, hardness, dimentional stability and stress-cracking resistance by adding a glass filler such as glass fiber (Japanese Patent Applications Laid-Open 199055/85 and 9456/86). However, adhesion between aromatic polycarbonate and a glass filler is insufficient, so that impact strength is extremely low in a molded product prepared from the composition of both.